ML document files are native to Meta Language programming language. ML file can store code writtne one of several varieties of the language. Meta Language was created in 1973, standardized in 1984, and received substantial upgrade in 2000.

ML files are broadly used in many various fields and processes, for example, in science and for creating code interpreters and compilers. ML file format stores data in plain text and such files can be edited using any standard text editor.